U.S Secretary of State Condoleezza Rice says the dispute over Iran's nuclear program must be handled now by the United Nations Security Council.
Rice rejected a Russian proposal to continue talks outside the U.N. She was speaking to reporters as she traveled to Chile for the inauguration of that country's new president, Michelle Bachelet.
Rice would not comment on when U.S. intelligence believes Iran will have a nuclear weapon, but she said the U.S. needs to move Iran from its "dangerous course" as quickly as possible.
Earlier Friday, President Bush called Iran's nuclear program a grave national security concern.
European leaders have said there's still time for a diplomatic solution that avoids action by the U.N.
The five permanent members of the Security Council were reconvening Friday to discuss an initial response to the dispute. They will recommend action to the full Council.
Officials in Tehran have threatened to cause the U.S. "harm and pain" if it takes the dispute to the Security Council.
The U.S. has not threatened military action against Iran, but U.S. officials have said Iran's uranium enrichment program is not acceptable.
On Wednesday, the 35-nation board of the International Atomic Energy Agency reported Iran to the Security Council for restarting uranium enrichment. The IAEA said it could not be sure that Iran is not enriching uranium for military use.
The Security Council could impose sanctions if it finds that Iran's activities violate the Nuclear Non-Proliferation Treaty.